Concise model of biofiltration based on a linear driving force concept, that takes into account adsorption of pollutant in the support phase and its biodegradation therein with the rate governed by a modified three-parameter Monod-type expression, was shown to be suitable to portray the transient behavior of biofilters arising from the periodic operation. Good agreement between simulations and experiments was obtained for the biodegradation of methyl-ethyl-ketone or n-butanol on a pre-selected bark bed in a broad range of operating conditions. (c) 2005 Elsevier Ltd. All rights reserved.